PS - Di - do you have or can you find a Samuel Gibson around that time?
I do have a Samuel GILSON - brother of the groom in this marriage - and that's why I thought this could be his signature

Thanks for possibilities to date ... I've been assuming this is a gent's signature but of course it could be a lady as per suggestions.
The groom had the following siblings: Sarah, Samuel, Rachel & Jacob (if I have the right family

)
Can't see any of those names in this signature (except for the "maybe" Sam'l )
Still guessing ...